1. (2022一上·宁海期末) 3+8=           6+7=           2+9=           3+6=           7+9+3=

4+7=           8-3=           12+5=           1+9=           10-4+6=

7+5=           9+3=           8+9=           4+9=           6+2-5=

7+7=           2+8=           4+3=           8-2=           17-4+3=

6+9=           12-10=         8+8=           14+3=           10-1-9=